System Architecture - Catalyst Communication Technologies

System Architecture

From the ground up, the Catalyst architecture is designed as a fault tolerant combination hardware and software solution to provide ease of use, system flexibility, functionality, and ease of system maintainability. The Catalyst architecture is a distributed and robust architecture with no central switch, built to minimize the impact of failure of any system component. It is based on the industry-standard Client-Server model.

Each Catalyst system is built with one or more state-of-the-art radio gateways. These gateways are the system “servers” in the Catalyst Client-Server architecture. Gateways are specific to the radio system or other communication system being supported; however, any mixture of gateways can be included in a system. For example, a system could consist of three Motorola gateways for SmartZone, two Harris Project 25 (P25) gateways, one Simoco Digital Mobile Radio (DMR) gateway, a Session Initiation Protocol (SIP) telephony gateway, and a Verizon Wireless LTE Push-to-Talk gateway. (Diagram below) All of these different communications platforms can be brought together for dispatch and interoperability through the Catalyst architecture. There is no limit to the number or type of Catalyst gateways that can be placed in a Catalyst system, and there are no limitations to the physical distance between gateway locations or console locations.

Each system also contains one or more of Catalyst’s client applications, most often Dispatch. The client applications are the user interface of the system. Catalyst offers three voice dispatch choices – our P25 and large system focused IP|Console™, our DMR and small to medium system Propulsion™ Console, and our lite version, Desktop Dispatch™. Catalyst also offers a standalone client called IntelliLink™ for managing advanced Interoperability and patch configuration, as well as a simple client for only enabling and disabling patches called the IntelliLink™ Gateway Dashboard. In the Catalyst architecture, interoperability is established between gateways, which is typically different than competing systems which establish interoperability at the Dispatch Client. A Dispatch client is not required for Catalyst Interoperability solutions.

All clients and servers in a system are connected together through an Internet Protocol (IP) network, which could be a Local Area Network (LAN) or Wide Area Network (WAN). The Catalyst solution has been carefully engineered to be a network friendly solution, an advantage that should not be underestimated when comparing Catalyst to competitive solutions. The Catalyst solution provides built in data compression algorithms, supports Transmission Control Protocol (TCP) for reliable network control information, and uses User Datagram Protocol (UDP) for efficient, low bandwidth voice traffic. Friendly configuration screens and standard network protocols provide for ease of installation and system maintainability.

Gateway Technology

Gateways in a Catalyst system can be either a wired interface solution or a wireless interface solution. A mix of wired and wireless gateways can be accommodated on any system.

Wired Gateways

The wired gateway solutions include Catalyst’s P25 standard Console Subsystem Interface (CSSI) and Digital Fixed Station Interface (DFSI) that are connected directly into various manufacturers’ P25 Radio systems, and the Digital Mobile Radio (DMR) Association standard wireline interface called the Application Interface Specification (AIS) – all via an Ethernet connection. The wireline radio gateways connect directly into the Radio Frequency Sub-System (RFSS) or base station via a single Ethernet connection for voice and control. These standards-based interfaces ensure compatibility with, and advanced control of, any radio manufacturers’ systems that also adhere to the P25 and DMR standards.

P25 Console Sub-System Interface (CSSI) – IP|CSSI™

This gateway provides direct Ethernet interface to various radio manufacturers’ P25 switch infrastructure via that manufacturer’s CSSI gateway. Multiple simultaneous audio paths can be routed through the Catalyst CSSI Gateway to provide a more robust solution compared with wireless system donor radio scanning.

P25 Digital Fixed Station Interface (DFSI) – IP|FSI™

This gateway provides direct Ethernet interface to up to four P25 conventional base stations, providing P25 digital audio, conventional audio, and control for IDs, emergency, and direct access to up to thirty-two channels.

DMR Application Interface Specification (AIS) – IP|AIS™

This gateway provides direct Ethernet interface to various radio manufacturers’ Tier III DMR trunked switch infrastructure via that manufacturer’s AIS gateway. Multiple simultaneous audio paths can be routed through the Catalyst AIS Gateway to provide a more robust solution compared to donor radio scanning.  The Gateway supports advanced features like unit ID, text message, priority (pre-empt), Individual Call, and Emergency.

LTE Push-to-Talk (FirstNet™)

Catalyst provides an advanced interface to LTE networks, including today’s pre-cursor to next generation FirstNet™ networks, enabling both dispatch to Push to Talk enabled cell phones and interoperability between Push to Talk enabled cell phones and LMR subscriber radios. The interface between Catalyst’s IP based system and the LTE/FirstNet™ infrastructure is through our CSSI interface to Kodiak Networks’ mission critical PTT solutions. This gateway provides a direct Ethernet interface to various commercial cellular carrier’s integrated Push-to-Talk service that use Kodiak’s solution.  Catalyst has leveraged the CSSI protocol to provide a robust, intelligent, standards-based integration that manages the flow of audio so syllables are not lost, displays the Unit ID of the cellular phone on the console, etc. For more information on the system architecture and capabilities of Catalyst and LTE/FirstNet™, visit our LTE web page HERE.

Intelligent Wireless Gateways

Catalyst’s wireless gateways implement a connection to a donor radio (or control station) which provides an interface to the radio systems, channels, talk groups, and individuals programmed into that radio. Many of Catalyst’s gateways provide intelligent control of the donor radio such that channel change, caller ID, emergencies, and other features can be controlled and managed at the dispatch console. These advanced control features are provided for DMR, P25 Trunked, P25 Conventional, NXDN Trunked, NXDN Conventional, EDACS™, MDC1200, FleetSync™, and others.

When a command is issued to a Catalyst gateway to perform a function such as to change systems or channels, the gateway provides feedback to the system to ensure the stated change has been completed. Catalyst’s advanced gateway technology also ensures successful communications by knowing when the radio system has assigned a channel. If there is no channel available, the gateway can automatically buffer the audio and wait to begin transmission until the audio can be safely routed. Competitive systems can lose portions of transmissions, which is unacceptable in critical communications. Advanced functions are radio dependent; contact Catalyst for details on your specific implementation.


Gateway software for Harris Trunked and Conventional P25, Opensky, EDACS™, and Analog Conventional solutions providing, when available, Unit IDs, Emergency, scan, and direct access to hundreds of channels or talkgroups. M7300 (XG-75M), M5300, and Unity (XG-100M) donor radios also provide digital rather than analog audio.  A single Unity mobile can instantly switch across VHF, UHF, 700, and 800 MHz.


Gateway software for Kenwood P25, LTR Trunking, FleetSync™, NXDN Trunked and Conventional, and MDC1200 providing Unit IDs, Emergency, scan, and direct access to hundreds of channels or talkgroups. Contact Catalyst for details regarding the specific donor radio and over-the-air protocol of interest to your organization.  A single NX mobile radio can support any two of DMR, NXDN, and P25 as well as conventional.

Basic Wireless Gateways

For radio systems that do not provide advanced control interfaces, Catalyst also supplies gateways that provide 2 or 4 wire Tone interfaces to a radio or even just a simple DC radio control. For telephony applications, Catalyst’s SIP gateway interfaces to SIP Telephony equipment through an Ethernet interface, and Catalyst’s PSTN gateway provides a standard RJ11C connection to a “plain-old-telephone-system”.

Public Switched Telephone Network (PSTN) – IP|PSTN™

Gateway software for console interface to a standard analog “plain-old-telephone system” (POTS) line. This type of connection is the same as having a land-line phone at your home.

Session Initiation Protocol (SIP) – IP|SIP™

Gateway software for console interface to a VoIP telephony path or SIP PBX system through a SIP Ethernet interface


Since 1999 Catalyst has fielded a variety of Radio over IP Gateways in addition to those listed above. Contact Catalyst to discuss your unique needs.


Not Radio over IP – Radio Control over IP. RCoIP™ provides the essential signaling and management for voice messages required for Critical Communications and is a step up from the more limited Radio over IP (RoIP). Catalyst pioneered this approach and was the first company to deploy advanced radio control over IP networks in 1999. RCoIP™ architecture is designed so that essential messages get through by using confirmed signaling, not best effort signaling. With nearly two decades of experience deploying mission critical voice solutions, Catalyst has created unique call flow management technology and has partnered with the major radio manufacturers to provide real-time feedback from your radio system to maximize call delivery.

Catalyst RCoIP™ provides unique but essential information required by Critical Communications users, such as Emergency, Unit ID, and channel availability. It allows dispatchers to choose from hundreds of channels on each Gateway and control functions like scan and encryption. Through our superior technology, partnerships with radio manufacturers, and outstanding customer support, Catalyst solutions are a force of innovation for Public Safety and other First Responders that need the highest level of mission critical communications.


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